String jsonText = '{"Data": {"attributes": {"type": "Contact","url":"/services/data/v35.0/sobjects/Contact/0036100000JUXKkAAP"},"Id": "0036100000JUXKkAAP","Description": "","LastName": "Testing"}}';

//Data - First nodes

//attributes - Second nodes

//type - Third nodes

Map<String, Object> cObjMap = (Map<String, Object>) JSON.deserializeUntyped(jsonText);

String cObjJson = JSON.serialize(cObjMap.get('Data'));

// Why again :(

Map<String, Object> cObjMapFurious = (Map<String, Object>) JSON.deserializeUntyped(cObjJson);

String cObjJsonDrunk = JSON.serialize(cObjMapFurious);

try

{

    SObject customObject = (SObject)JSON.deserialize(cObjJsonDrunk, Sobject.class);

    System.debug(' sObject: '+customObject);

}

catch(Exception ex)

{

    System.debug('Error: '+ex.getMessage());

}

public void sendAccount(String salesForceAccountID, Integer accountID, String priorityCode, String lastActivityDate, Boolean signUpReview) {

            Map<String, Object> requestBody = new Map<String, Object> {

                'SalesForceAccountID' => salesForceAccountID,

                'AccountID' => accountID,

                'PriorityCode' => priorityCode,

                'LastActivityDate' => lastActivityDate,

                'SignUpReview' => signUpReview

            };